Aminoacyl-tRNA synthetases are key enzymes in protein synthesis and act as interpreters of the genetic code by relating amino acids to specific tri-nucleotides through aminoacylation of their cognate tRNAs. As such, their structure/function relationships provide important insights into early systems of the decoding machinery. This application describes a proposed workshop, entitled "Aminoacyl-tRNA Synthetases in Biology, Medicine, and Evolution," to be held at the Asilomar Conference, California, from September 23-28, 2001. Owing to the rapid pace of progress and interdisciplinary nature of the synthetase field, organization of this workshop is necessary. The format of the meeting will follow a Gordon Research Conference schedule, with a total of nine formal scientific sessions held in the mornings and evenings. Poster sessions and informal scientific discussions will take place in the afternoons. In each session, major talks of approximately 30 minutes duration will be given by senior investigators, and two to three additional short talks will also be presented by speakers selected on the basis of submitted abstracts. The nine sessions will focus on core issues of tRNA synthetase structure and function, as well as on additional topics of emerging interests. These include the mechanisms of specificity and editing, recognition of tRNA and tRNA-like molecules, alternative functions of synthetases, and artificial aminoacylation systems. This Asilomar meeting represents a unique opportunity to bring together both senior investigators in the field and younger scientists who are still establishing their careers. Participants will be chosen from a highly interactive group of scientists from a variety of disciplines, including representatives from the United States, Europe, and Japan. This is the fourth such meeting to be held in the last decade, with previous meetings held in Autrans, France (1990), Taos, New Mexico (1997), Mittelwihr, France (1998).